Process for treating milk.



T. G. MOLLINGER.

PROCESS FOR TREATING MILK. APPLIOATION FILED SEPT. 22; 1910.

2 SHEBTS-8HEET 1.

T. G. MOLLINGER.

PROCESSTOR TREATING MILK.

APPLIOATION FILED SEPT. 22, 1910 Patented 001;. 10, 1911.

2 SHEBTB-SHEET 2.

THEODORE G. MOLLINGER, F KALAMAZOO,

MICHIGAN, ASSIGNOR TO STEPHEN B.

MONROE, TRUSTEE, OE KALAMAZOO, MICHIGAN;

PROCESS FOR TREATING MILK.

To all whom it may concern:

Be it known that I, THEODORE G. MOL- LINGER, a subject of the Queen of the Netherlands, and now fu] Improvements in Milk, of which fication.

In the accompanying drawings, I- illustrat-e an apparatus such as I prefer to use in carrying out my improved process, the various parts thereof being shown mainly in conventional form, and without particular regard to scale or proportions.

Processes for Treating the followingis a speciratus for carrying out my improved process, certain of the parts being shown in conventional form, they being illustrated merely for the purpose of illustrating the general arrangement of the apparatus and the connections for the various parts thereof. Fig. 2 is a vertical longitudinalv section through the heating and cooling elements, the connections being shown in full lines. Fig. 3 is an enlarged transverse section through the cooling element, taken on a line correspondiug to line 3-3 of Fig. 2. Fig. 4 is an end view of the heating element, looking from the left of Fig. 2. Fig. 5 is a transverse sec line corresponding to line 5-5 of Fig. 2.

ln the drawings, similar reference characters refer to similar parts throughout the several views, and the sectional views are taken looking in the direction of the little arrows at the ends of the section lines.

The essential sides in the exposure of the milk to a relatively high temperature within definite liinits and considerably in excess of the boiling point of milk, such exposure being so controlled as to be practically momentary and the milk being under substantial pressure. This step is immediately followed by the very rapid cooling of the milk, down to a point closely approximating, but not higher than, the boiling point. This is again followed by a more protracted, but still definitely limited, period of cooling down to a 0 temperature in excess of normal, after which the milk is allowed to cool throughout the remaining range of temperature, down to normal, without specific control.

Referring to the accompanying drawing,

5 1 represents the heating element and 2 the Specification of Letters Patent. Application filed'septemher 22, 1910. Serial No.

residing at Kalamazoo, 5 Michigan, have invented certain new and use- Figure'l is a side elevation of an appa tion through the heating element, taken on a principle of my process re- Patented Oct. 10, 1911.

cooling element. The heating element is connected to deliver to the cooling element through a pipe 3, the milk being delivered to the heating element through the pipe 4 by means of a pump 5, which is shown herein in conventional form.- The tank 6 represents the supply of milk and is connected to the pum through the pipe 7. The treated milk is de ivered through the pipe 8 to a delivery receptacle 9, which has a drawofl' faucet 10 controlled as 11.

The pipe 8 is preferably provided with a pressure regulator 12, so that the desired pressure may be maintained on the milk as it is forced through the heating'a-nd cooling elements by means of the pump. A steam pump is preferably used, as it is desirable ordlnarily to maintain high pressure, and to force the milk rapidly through the heating and cooling elements.

The heating element 1 preferably consists of a cylindrical jacket 13, a pipe of about four inches diameter being found practical. The pipe is provided with heads or caps Hand 15. Steam is admitted to the jacket by the pipe 16 connected to the head and is discharged through the pipe 17 connected to the head 14. The supply pipe 4 is connected to the inlet end of the coil arranged within the jacket. Steam is sup- )lied from a suitable source, so that it may 0 delivered under high pressure to secure the desired temperatures.

The heads 14 and 15 are provided with plug-like end pieces 18 and 19, respectively, which are adapted to receive the ends of a plurality of tubes. forming the coil, the structure illustrated having 5 tubes as 20, 21, 22, 23 and 24. See Figs. 2, 4 and 5. These tubes are preferably of copper about of an inch internal diameter and about ten feet long. They are preferably open at each end for convenience in cleaning. These tubes are connected to form a single coritinuous channel. The connections in the structure illustrated are the headers 25 and 26, which are removably clamped against the outer faces of the pieces 18 and 19, respectively, screw bolts, as 27, being provided in the structure illustrated for the purpose. These headers are provided with channellike passages 28, the ends of which register with the pipes to be connected. At the left hand end of Fig. 2 the channels are show-n by a suitable valve,

' in cross section, they are. also indicated by dotted lines; in Fig; 4. The channels at the from the intake pipe right handend'of the heating element are shown by dotted are thus connected lines in Fig. 5.. Thepipes so that the milk passes to the outlet pipe 23 of the heating'element which is connected by the pipe 3 to the cooling element. 1

A thermome er' 31 is provided for" the heating element, it being preferably mountjacket is a plurality of end. The vpipe-3 is connected to deliver to the header 38, while the header 39 is con- 25 nected'to the discharge pipe 8. Couplings are preferably rovide for the pipe 3 adapted to be rea 1y removed.

A thermometer 40 is preferably arranged at the discharge end of the cooling element.

The headers are preferably removably secured, so that the pipes of the cooling element can be readily cleaned. These 'pipes .are also formed of cop er and are of about the same diameter as t e pipes forming'the coil of the heating element. In'the structure illustrated, thls is accomplished by providing the heads with flanges 41 and the headers with end plates 42, the parts being clamped together by the bolts 43.

he cooling fluid isdelivered to the jacket by means of the pipe 44 and is discharged therefrom'through the pipe 45.

The reservoir 9 1s provlded with a vent 46 which is screened by a mass of 'cotton'or other suitable material. This reservoir is also provided with a steam inlet 47, by which the water and steam may be introduced for cleaning and sterilizing the reservoir.

With the parts thus arranged, thejmilk to be treated is delivered from the supply 6 by means of the pump, first to the heating element, then. to the cooling element and then I to the delivery tank.

The pump is, as stated, adapted to deliver the milk under in elements and also, it is desirable to main tam the pressure while the milk is' being treated, in order to secure the most satisfactory roduct.

.It wi be noted that the heating element exposes the milk to the heat in a relatively small or attenuated body or stream. The cooling element also exposes the milk in a small or attenuated body or stream, the difin the cooling element.

20, which is connected to the milk supply pipe 4, by a coupling 29,

high pressure, so that it is 'rapidly forced through the heating and coolference bein that there is preferably a continuous sing e passage for the milk in the heating element-and a plurality of passa es This causes 51c milk to flow more rapidly while being heated than while bein cooled. This rapid movement of the mifk through the heating element keeps it pro erly agitated so that it is evenly heatedang prevents its burning. The presentation of the milk to the heat in the attenuated body or stream makes it possible to accomplish the desired heating rapidly.

In treating milk by my improved process, the heating and cooling elements are brought .to the proper temperatures and the milkforced therethrough by means of the pump. Sweet milk, preferably as fresh as possible, is introduced at it's normal temperature, for

instance, about 20 centigrade, that is, no

preliminar heating or coolin is required. The milk is forced through the apparatus, by means of the pump, under conslderable pressure, preferably of about 600 pounds 'per square inch, which however, may be materially varied, and at such a rate that the time of passage through the heating element shall be preferably about two seconds, and that preferably the time of passage through the cooling element shall be similar.

The heating element is maintained at a temperature suflicient to raise the milk, in

its passa 'e through the same, to a temperature preferably of about 138 centigrade at the time of its exit therefrom. The temperature, to which the milk is ultimately thus raised, may vary within certain limits, but should not be substantially less than 130 centigrade, nor substantially more than 155 centlgrade. The. temperature of the steam in the heating element may, of course, be higher than the maximum limit above mentioned for the milk, depending upon the conductivity of the apparatus, the initial temperature of the milk, or other conditions.

Upon passing to the cooling element, the temperature of the milk is reduced to a point not substantially exceeding its boiling' {point and referably about 98 centigrade. This coo ing action should preferably take place with a rapidity substantially equal to that of the heating. The milk, having been received in the reservoir 9, and the pressure having been reduced, is then inclosed, preferably as soon as possible, in vessels which have been sterilized by heat, and whose temperature should preferably correspond substantially with that of the milk at this stage, the vessels bein filled as nearly .full as possible and prom t y sealed. The subsequent cooling of the m1 k down to a temperature of about centigrade, is thereupon controlled in any convenient manner, so that a substantial period, preferably Milk when thus treated, is thoroughly sterilized without any substantial impairment of color or breaking of the cream line, and retainsthe flavor of new untreated milk.

I employ the term bottling, as a convenient one to describe the inclosu're of the milk in any suitable vessel, and it will therefore be understood that. said term does not imply any limitation as to the character of the vessel.

l have specified above the preferred temperatures and periods which give the best results in my process, but it is proper to state.

that some variation therefrom 1s permissible; thus, the milk may be raised to a tern.- perature between 130 and 155 cent-igrade, but these limits should not be exceeded in either direction. The period of actual maintenance of the milk at the maximum ternperature should be momentary, preferably only the fraction of a second, although the actual passage through the heating and cooling elements, during which the temperature is raised and lowered is of course longer. Under no circumstances should themilk be maintainedat a temperature above 130 centigrade, for more than two seconds. The primary cooling to about 98 centigrade should, as before stated, be very ra id, and should preferably correspond in uration with that of the heating, and the secondary cooling from about 98 centigrade to about 70 centigrade, while prolonged during a substantial period, in order to subject any new bacteria to destructive exposure to heat, should not be protracted substantially beyond thirty minutes.

I amaware that the sterilization of milk by the controlled application of heat, is not broadly new, and I am also aware that it has been proposed to sterilize fluids, includ ing milk, by exposin them to a temperature considerably above t e boiling point, as set forth in Letters Patent of the United States No. 786,819, dated April 11th, 1905. I, therefore, do not broadly claim the brief exposure of milk to high heat, for I have found by actual experience that such exposure must not only be definite but must be attended by the definite control of the subsequent cooling, in order to produce the desired result of sterilizing the milk without impairment of its qualities. The essence of my invention-resides in the organization and successive steps of treatment both in regard to temperature and periods of duration whose limits are above set forth.

Having thus described my invention, what I claim as new and desire to secure by Letters Patent, is:

The hereinbefore described process for the sterilization of milk, which consists in the heating of an attenuated body of milk to a temperature not substantially less than 130 Centigrade or substantially more than l centigrade, during a period not substantially exceeding two seconds; the primary rapid cooling of the milk to a temperature ofv about 98 centigrade; the bottling and sealing of the milk; and the prolonged secondary cooling of the milk to a temperature pf about 70 centigrade.

In witness whereof, I have hereunto set my hand and seal in the presence of two witnesses.

THEODORE G. MOLLINGER. [1,. s.)

Witnesses: i

M. Puma WOODRUFF, CLARA E. Barman. 

